1. Field of the Invention
The present invention relates to an acoustic component mounting structure for use in portable radio units.
2. Description of the Related Art
According to a conventional acoustic component mounting structure for use in portable radio units, as shown in FIGS. 1 and 2 of the accompanying drawings, a holder 9 with an acoustic component 7 mounted thereon is hooked on a circuit board 6, which is mounted in a front case 1 by circuit board hooks 15. The acoustic component 7 thus placed in the front case 1 is pressed against a gasket 91 mounted in the front case 1.
The conventional acoustic component mounting structure is problematic in that since dimensional variations of the holder 9 and the circuit board 6 affect the positional relationship between the gasket 91 and the acoustic component 7, the hermetic sealing provided between the gasket 91 and the acoustic component 7 also varies due to the dimensional variations of the holder 9 and the circuit board 6, tending to result in an acoustic characteristic degradation due to sound leakage.
Another problem of the conventional acoustic component mounting structure is that because many parts are required to secure the acoustic component 7 in position, the available area for mounting parts on the circuit board 6 in the front case 1 is limited.
It is therefore an object of the present invention to provide an acoustic component mounting structure for use in portable radio units which reduces positional variations between an acoustic component and a gasket for increased reliability of acoustic characteristics, and allows the available area for mounting parts on a circuit board to be utilized effectively.
According to the present invention, an acoustic component mounting structure for use in a portable radio unit has a portable radio unit housing having a cavity defined in a surface thereof, a decorative panel mounted on the portable radio unit housing in covering relation to the cavity, and an acoustic component housed in the cavity and sandwiched between the portable radio unit housing and the decorative panel.
The portable radio unit housing may have a recess defined in a surface thereof, the decorative panel being held in the recess, the cavity being defined in a bottom of the recess.
The acoustic component mounting structure may further have an electric conductor inserted into the cavity and connected to the acoustic component, the cavity having a through hole defined in a bottom thereof, the electric conductor extending through the through hole into the portable radio unit housing.
The electric conductor may comprise a connecting terminal which comprises a metal plate.
Alternatively, the electric conductor may comprise a flexible board.
The decorative panel may have a through hole defined therein at a position facing the acoustic component for passing guiding sounds produced by the acoustic component out of the portable radio unit housing.
The acoustic component mounting structure may further comprise a gasket mounted on a reverse side of the decorative panel in surrounding relation to the through hole, and pressed against the acoustic component.
The acoustic component mounting structure may further comprise an adhesive tape attached to a reverse side of the decorative panel and fixing the decorative panel to the portable radio unit housing.
The hermetic sealing of an acoustic space defined in front of the acoustic component is basically determined by the accuracy with which the portable radio unit housing has been molded. Since the accuracy with which the front case is molded can easily be controlled, the hermetic sealing of the acoustic space can sufficiently be achieved.
Furthermore, because the acoustic component is directly held by the portable radio unit housing, no parts are required to secure the acoustic component in position.
The above and other objects, features, and advantages of the present invention will become apparent from the following description based on the accompanying drawings which illustrate examples of preferred embodiments of the present invention.